Muzzle mounted bore sight



. 3am, OR 293839466 5R Seamh 154 Aug. 28, 1945. BROWN 2,383,466 MUZZLEmounmn BORE SIGHT 4 Filed Dec. 20, 1943 ea ii 0 Len H Brawn.

33. GEOMETWCZKL \tiSTRUMENlb.

Patented Aug. 28, 1945 UNITED STATES PATENT OFFICE (Granted under theact of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) 12Claims.

The invention described herein may be manufactured and used by or forthe Government for governmental purposes without the payment to me ofany royalty thereon.

In the operation or bore sighting a gun, it is customary to supportcross wires over the muzzle. Various devices for this purpose are knownin the art. The bore sighting operation consists generally in sightingboth the gun axis and an externally mounted sighting instrument on adistant object, such as a star, for the purpose of truing the instrumentwith respect to the gun axis. The distant object or target is sighted onthe projected axis of the gun barrel by reason of the fact that thecross wires are so located that they intersect on the gun barrel axis.

The particular object is to provide a mechanical means for mounting thecross wires in the muzzle, together with a bore sight inserted in thechamber of the gun, both parts being assembled as a compact unit whennot in use. The cross wires are carried by a ring adapted for insertionin a cup which carries the sighting aperture. One of the parts carries acoil spring which is compressed between the part in the assembledcondition. The ring is retained under tension within the cup by means ofa latch or trigger carried by the latter. In use, the assembly isinserted in the chamber of the gun and the latch or trigger thenreleased, whereupon the ring is projected by means of a spring into themuzzle. Thus the operator need not expose himself to enemy fire whileapplying the cross wires to the muzzle.

An illustrative embodiment of the invention, is disclosed in thefollowing description and in the accompanying drawing in which:

Figure 1 is a longitudinal section of a gun barrel and of the devicemounted therein in its operative condition;

Figure 2 is a similar section on a larger scale, showing the device inits assembled condition, and

Figure 3 is a perspective view showing the parts in their operativeposition.

In Figure 1 is shown a conventional gun barrel I having at its forwardend a muzzle 2, at its rear end a chamber 3, and a forcing cone 4between the chamber and the bore 5. The device for supporting the crosswires in the muzzle,

for the purpose of bore-sighting, is a ring 6 adapted to fit accuratelyin the muzzle 2 as clearly shown in Figure 1. The forward end of thering may be flanged inwardly at 1 to carry the cross wires 8 which areso positioned that they intersect at the axis of the gun barrel forcentering the bore-sighting target as stated above. The rear end of thecup 6 is also flanged inwardly at 9 for a purpose that will presently bedescribed. A coil spring III has one end fixed to the ring 6 while theremainder of this spring, when unrestrained, lies outside of the ring.The purpose of the spring will also be described hereinafter.

The device for providing a sighting aperture in the chamber 3 includes acylindrical cup I I adapted to fit accurately in the chamber 3 andpreferably against the forcing cone 4, as shown in Figures 1 and 2. Thebottom I2 of the cup is disposed rearwardly and is formed with a centralsighting aperture or peephole I3. Against the bottom I2 is secured aguide tube I4 disposed centrally within the cup. A string or cord I5 hasits ends fastened respectively to the guide tube and to the free end ofthe spring III.

The ring 6 is of such size that it may be nested within the cup II inassembling the parts in this manner. The spring I0 is compressed andpositioned around the guide tube I4. The assembly is maintained, againstthe pressure of the spring. by means of a latch or trigger I6 pivotallymounted in the cup bottom I2 and adapted to hook On the rear flange 9 ofthe ring 6, as shown in Figure 2. Since the flange 9 extends around theentire periphery of the ring 6, no circumferential alinement of the ringwith the latch is necessary.

When the bore sighting apparatus is to be used, the assembled device isinserted in the chamber 3. The latch or trigger I6 is then released fromthe flange 9, whereupon the compressed spring III projects the ring withits cross wires into its operative position in the muzzle of the gun asshown in Figure 1. The outer cylindrical surface of the ring 6 alinesthis portion of the device accurately in the muzzle. A finger piece Ilmay be fastened to the outer surface of the bottom I2 of the cup II forthe purpose of pulling the entire device out of the gun.

By means of the apparatus herein described, the bore sighting operationmay be performed from within the protective enclosure. The operator isnot required to expose himself to enemy fire by going to the muzzle ofthe gun for mount- I ing the cross wires in the conventional manner.

This characteristic of the invention is especially valuable in tankwarfare.

While the specific embodiment of the invention has been shown anddescribed, it will be understood that various alterations may be madewithout departure from the spirit of the invention as indicated by theappended claims.

What I claim is:

1. A bore sighting device comprising a frame member adapted to be fittedin the muzzle of a gun, cross-wires carried by said member, a cup memberadapted to be fitted in the chamber of the gun and of such size as toreceive said frame member, said cup having a sighting aperture throughits bottom, a spring carried by one of said members and positioned to becompressed on insertion of the frame member into the cup member, and alatch carried by one of said members and engageable with the othermember for retaining the inserted member against the pressure of thecompressed spring.

2. A bore sighting device comprising a frame member adapted to be fittedin the muzzle of a gun, cross-wires carried by said member, a cup memberadapted to be fitted in the chamber of the gun and of such size as toreceive said frame member, said cup having a sighting aperture throughits bottom, a spring carried by one of said members and positioned to becompressed on insertion of the frame member into the cup member, a latchcarried by one of said members and engageable with the other member forretaining the inserted member against the pressure of the compressedspring, and a cord having its ends connected respectively to saidmembers.

3. A bore sighting device comprising a frame member adapted to be fittedin the muzzle of a gun, cross-wires carried by said member, a cup memberadapted to be fitted in the chamber of the gun and of such size as toreceive said frame member, said cup having a sighting aperture throughits bottom, a spring carried by one of said members and positioned to becompressed on insertion of the frame member into the cup member, a latchcarried by one of said members and engageable with the other member forretaining the inserted member against the pressure of the compressedspring, and a guide for said spring carried by the member in which thespring is to be inserted.

4. A bore sighting device comprising a frame member adapted to be fittedin the muzzle of a gun, cross-wires carried by said member, a cup memberadapted to be fitted in the chamber of the gun and of such size as toreceive said frame member, said cup having a sighting aperture throughits bottom, a spring having one end fastened to said frame member andadapted to be compressed on insertion of said frame member into said cupmember, and a latch carried by said cup member and engageable with saidframe member for retaining the latter against the pressure of thecompressed spring.

5. A bore sighting device comprising a frame member adapted to be fittedin the muzzle of a gun, cross-wires carried. by said member, a cupmember adapted to be fitted in the chamber of the gun and of such sizeas to receive said frame member, said cup having a sighting aperturethrough its bottom, a spring having one end fastened to said framemember and adapted to be compressed on insertion of said frame memberinto said cup member, a latch carried by said cup member, and an inwardflange on said frame member engageable by said latch for retaining saidframe member against the pressure of the compressed spring.

6. A bore sighting device comprising a frame member adapted to be fittedin the muzzle of a gun, cross-wires carried by said member, a cup memberadapted to be fitted in the chamber of the gun and of such size as toreceive said frame member, said cup having a sighting aperture throughits bottom, a spring having one end fastened to said frame member andadapted to be compressed on insertion of said frame member into saidcupmember, a latch carried by said oup member and engageable with saidframe member for retaining the latter against the pressure of thecompressed spring, and a cord having its ends connected respectively tosaid members.

7. A bore sighting device comprising a frame member adapted to be fittedin the muzzle of a gun, cross-wires carried by said member, a cup memberadapted to be fitted in the chamber of the gun and of such size as toreceive said frame member, said cup having a sighting aperture throughits bottom, a spring having one end fastened to said frame member andadapted to be compressed on insertion of said frame member into said cupmember, a latch carried by said cup member, an inward flange on saidframe member engageable by said latch for retaining said frame memberagainst the pressure of the compressed spring, and a cord having itsends connected respectively to said members.

8. A bore sighting device comprising a frame member adapted to be fittedin the muzzle of a gun, cross-wires carried by said member, a cup memberadapted to be fitted in the chamber of the gun and of such size as toreceive said frame member, said cup having a sighting aperture throughits bottom, a spring having one end fastened to said frame member andadapted to be compressed on insertion of said frame member into said cupmember, a latch carried by said cup member and engageable with saidframe member for retaining the latter against the pressure of thecompressed spring, and a guide for said spring carried by said cupmember.

9. A bore sighting device comprising a frame member adapted to be fittedin the muzzle of a gun, cross-wires carried by said member, a cup memberadapted to be fitted in the chamber of the gun and of such size as toreceive said frame member, said cup having a sighting aperture throughits bottom, a spring having one end fastened to said frame member andadapted to be compressed on insertion of said frame member into saidcup, a latch carried by said cup member, an inward circular flange onsaid frame member engageable by said latch for retaining said framemember against the pressure of the compressed spring.

10. A bore sighting device comprising a frame member adapted to befitted in the muzzle of a gun, cross-wires carried by said member, anapertured sighting member adapted to be fitted into the chamber of thegun, said members being shaped to be assembled one to the other, aspring carried by one of said members and positioned to be compressedwhen said members are assembled together, and a latch carried by one ofsaid members and engageable with the other member for retaining saidmembers in mutually assembled condition against the pressure of thecompressed spring.

IL A bore sighting device comprising a front sight means constructed andarranged to fit within the muzzle end of a gun, a rear sight meansconstructed and arranged to fit within the chamber of the gun, said twosight means telescoping one within the other, and resilient 33.GEUMETFHCAL .%-'iSTRUMENT$,

wi W??? tioned member from the chamber to a position in the bore of thegun remote from the chamber of the gun while the said second memberremains within the said chamber, and sighting means on each of saidmembers which lie substantially in the axis of the gun when the saidfirst mentioned member has been pushed away from the said secondmentioned member.

LEO H. BROWN.

